Garage Q&A, Tech Answers - June 2014

Keep Those Classic Ford and Mustang Tech Questions Coming!

David Stribling

May 13, 2014

Alignment Assignment

I have a '65 Fastback with the Shelby drop, TCP upper/lower control arms, TCP strut rods, and TCP power rack-and-pinion steering. The left front wheel sits forward in the fender wheel opening, and on occasion rubs the lower-forward section of the fender. The right front wheel fits center in the fender wheel opening, and doesn't rub whatsoever. I took the car in for an alignment, and the alignment shop states the front is perfectly aligned. The alignment report shows:

What options/suggestions do you have to move the driver-side wheel “back” within the fender to prevent the rubbing and look centered within the fender opening?

Scott
Via the Internet

I don't see anything wrong with the alignment numbers (although I may want to equalize the camber, but no biggie). Let's go over some things on the chassis to make sure that there isn't the problem there. Damage, and repairs to the damage, may have caused the rubbing on the driver side.

1. First, check on your alignment sheet and see if it shows how square the wheels are to each other. The one nice thing about four-wheel laser alignment is they can show you just how square the four wheels are riding down the road. The front wheels may be in alignment, but if the mount point on one side or the other has been moved due to damage or framerail replacement, it will show up here. If they didn't check it, have it checked. If they are square, then you have a body issue—not a frame issue.

2. You didn't mention what type of TCP control arms you have. The older-style arms used a template to lower the control arm mount holes (Shelby Drop), where the newer ones have the drop down in the upper shafts built in. If you have the older style, make sure the template was used properly in drilling the holes. Its not a straight drop—the angle has to be right.

Make sure they were done properly. The alignment would probably show this, but confirm it just in case.

3. Take a look at the length of threads coming out of your TCP strut rods. If there is a significant difference in the length (the nut is down the shaft farther on one side), then he had to do a lot to get one side or the other to come into spec for the caster. This could signal you that there may be some frame damage on the vehicle. Or, it may show that the car was repaired, but the alignment points on the repair parts are not the same. I have seen that in the past.

4. Some replacement fenders are not up to snuff. I have seen some of the cheaper panels be off as much as ½ inch on the wheel openings. Some of the reallybad ones I have had to trim the buckets back a ½ inch just to get the headlights to fit. With the car sitting level on level concrete, tape a string to the front of the wheel lip and the back of the wheel lip with a weight hanging down so gravity is pulling it. Pick a central point, using identical points on the car (the front two tie down holes in the frame) and measure the distance to the openings on the opposite side of the car. The measurements should be the same. If not, you may have a replacement panel that is not to spec, a bent frame, the front end panels may not be aligned on the car properly, or a combination of all the above.

5. Look over your frame for any kind of tweak. A small kink can really affect the overall straightness of the car. With the old 14-inch wheels and tires it wasn't a big deal, but with modern rubber it makes a big difference. And the way these cars are built, the front end can be on the car straight but the frame is kinked saideways, or vice versa.

6. Taking the car to a frame rack usually isn't too expensive. They can tell you if it is straight fairly reasonably. It starts getting unreasonable if they have to straighten it—that's where they make their money! But for your street/strip car, if none of the above finds the problem, then I would have it checked.

Good luck and send me a follow-up.

Hump Day

On the 351W D0OE-C heads, can the thermactor hump be removed to help increase the exhaust gas flow in the ports?

Thank you for any help you can provide.

Greg Plubell
Sherman, TX

The little hump in the exhaust port of the 351W heads can and should be removed when prepping these heads for performance. Unlike a small-block Chevy head, the good old 351W head used from 1970 through 1974 is a good piece; and with just a mild port match on the intake side and removal of the exhaust bump, they will flow more than 200 cfm without breaking a sweat. My builder always takes them out. You need to do more work to the Chevy head to get those kinds of numbers.

Be wary, though, on the intake side. Guys who try to push these heads too far get a rude awakening on the third pass at the dragstrip. Too much grinding on the intake side can make the walls thin between the intake and water jackets, and the engine will burn through to the water jackets and you're toast. Two hundred cfm is good for a nice street engine. Don't try to push them further. Why? Because the new cast-iron and aluminum heads are better out of the box, and by the time you pay for the extra porting, weld-ups, and more, you could buy a set of Edelbrocks or Darts or whatever, and get more than 230 cfm right out of the box.